Household Mold Tips

Understanding Household Mold

The growth of mold is common in Southern climates and can occur anywhere and typically appears as a black/gray, yellow, or green growth.   Mildew is a fungus that spreads as microscopic spores are carried by the wind. When the spores land on a surface, they feed either on the surface itself or on organic airborne dirt and pollen that has accumulated on the surface.  The growth of mildew/mold is encouraged by moisture, warmth, lack of air circulation and organic nutrients, and darkness. (North elevations of buildings are susceptible in particular.)  Since the spores travel through the air, their behavior tends to be erratic. During rainy periods, the mildew can appear on previously unaffected  areas.

If you have mold inside your home it's because there is moisture which shouldn't be there.  We have high humidity in the South, but there are good ways to help control the humidity in your home through the use of dehumidifiers, or HVAC control systems for your current air conditioning systems.  Humidity should be maintained at 45% to 50% inside to inhibit the growth of mold. If you are experiencing mold in unusual areas inside your home, then you have a moisture issue which should be investigated and resolved. Maintaining the temperature and the humidity in a home is important to the longevity of the wood floors, doors, trim, rate of expansion and contraction of many materials in a home, and indoor air quality. Drastic temperature and humidity changes in the internal environment of a home is not recommended.

It's important to maintain the exterior of your home by washing it on a regular basis as needed.  A significant food source for mildew is pollen and dirt.  If it is left on the surface whether it is on the roof shingles, stucco, brick, cypress, stone or other materials, with adequate moisture and shade, mold will take hold and grow and spread.  The best way to extend the life of the exterior finishes of a home is with a regular washing (not high pressure).  Consult a local paint store for the most current additives for proper washing, and suggestions or contact us for a recommendation. The longer you wait and leave the mold and mildew unattended, the more it will deteriorate the finish and life of many of these materials. Many cleaners and preventatives of mildew growth, like "Mildew-Check by PPG", and "Olympic Mildew Check" do an excellent job of cleaning and/or preventing the growth of mildew and mold.  See the NAHB Mold Tips for further information.

Fungus likes warm, moist, shady locations, such as under eaves, near or behind bushes, shrubbery and trees and on soffit materials and walls that may be frequently shaded from the sun. Areas of mildew growth may often start on the Northern exposure side of the home, as would also occur on the Northern side of a tree in the forest. However, during humid and/or rainy periods, mildew/mold can obtain a foothold on virtually any exterior area. Check your lawn sprinkler systems too, make sure the exterior of your home finishes are not regularly receiving spray from the lawn sprinklers.

  Always maintain a clean exterior free of vine growth and plant growth. Plants too close to the exterior structure of the home can create a restriction of air circulation around the materials of the home and thereby contribute to excessive growth. The look of vines and other plant materials may be nice, but the damage caused by such a look can be serious to the water proof barrier, window seals, and seals between similar and dissimilar materials, while creating a prime environment for mold and mildew.  

Prior to cleaning any roofs, it's important to check with the manufacturer of your shingles to verify how exterior cleaning may affect your roof warranty.  Most shingles contain mildew inhibitors, and over time, these inhibitors loose their ability to protect your roof from mold damage.  There are products that can help keep your roof clean of mold and mildew through the application of inhibitors or installation of zinc strips type products.

*Note: This content is for informational purposes only. McNair Building Construction, inc. makes no warranties and bears no liability for use of this information. The information is not intended, and should not be construed, as legal, tax or investment advice, or a legal opinion. Always contact your legal, tax and/or financial advisers to help answer questions about your specific situation. If you need specific construction, building or maintenance advice about your particular situation, please contact our office prior to taking any action. If you have excessive mold growth, contact us for professional advice and the proper way to remove and inhibit mold growth.  To read more about maintenance, register at


National Association of Home Builders   Hilton Head Area Home Builders Association   Hilton Head Chamber of Commerce   Project Management Institute   International Code Council   Dun & Bradstreet  

843-681-9543 • Moss Creek Village, Suite 300, 1533 Fording Island Road Hilton Head, SC 29926 •